Sömmering is the lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

-flooded remains of a lunar

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 on the eastern edge of the Mare Insularum

Mare Insularum

Mare Insularum is a lunar mare located in the Insularum basin just south of Mare Imbrium. The basin material is of the Lower Imbrian epoch, with the mare material of the Upper Imbrian epoch. The mare is bordered by the craters Copernicus on the east, and Kepler on the west...

. To the southeast is the crater Mösting

Mösting (crater)

Mösting is a small lunar crater that is located in the southeastern fringes of the Mare Insularum. The ruined crater Sömmering lies to the northwest. To the southeast is the large crater-bay of Flammarion. Mösting has a terraced inner wall and a small central hill at the mid-point of the floor.To...

, and north of Sömmering lies a similar flooded crater designated Schröter

Schröter (lunar crater)

Schröter is a lunar crater near the mid-part of the Moon, on the eastern Mare Insularum, and named after German astronomer Johann Hieronymus Schröter. It lies to the north of the craters Sömmering and Mösting. To the southeast of the crater rim is a rille named the Rima Schröter...

. A rille

Rille

Rille is typically used to describe any of the long, narrow depressions in the lunar surface that resemble channels. Typically a rille can be up to several kilometers wide and hundreds of kilometers in length...

 designated Rima Schröter runs from the southeast of Schröter towards the east of Sömmering's outer rim.

The western rim of this crater forms a slender arcing rise on the lunar mare

Lunar mare

The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...

, with a wide gap to the south and a narrow gap in the north. The eastern rim is much thicker in girth, and resembles a curved ridge. The interior floor is level and nearly featureless. The open southern end of this crater overlaps the lunar equator.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Sömmering.

Sömmering	Latitude	Longitude	Diameter
A	1.1° N	11.1° W	3 km
P	2.2° N	10.3° W	6 km
R	1.9° N	9.8° W	17 km